1. Field of The Invention
The present invention relates to a process for the production of a new biological polymer and, more especially to a process for the preparation of a new biological polymer by a fermentation method using methanol as a source of carbon and energy.
The invention is also concerned with new biopolymers i.e., heteropolysaccharides falling within the category of biological polymers.
2. Description of The Prior Art
The polysaccharide which has been known is the xanthan gum produced by the fermentation of the genus Xanthomonas strain in a culture medium which generally utilizes carbohydrate such as glucose as a source of assimilable carbon. The xanthan gum has a high molecular weight of about 2.times.10.sup.6 dalton, and consists of glucose, mannose and glucuronic acid. As a small amount of xanthan gum can exert a high viscosity, it may be useful as a viscosity control agent or a suspending agent for a solid-in-water and/or oil-in-water dispersion, and it may be applied in the secondary recovery of petroleum by water flooding (ACS Symposium Series No. 45, 144-160, 1977).
According to the fermentation method, the xanthan gum can be prepared by culturing Xanthomonas campestris on a culture medium (Adv. Appl. Microbiol., 23, 19-49, 1973) consisting of a 2-5% carbohydrate such as glucose and sucrose as a carbon and energy source and a 0.3% slurry from alcohol fermentation. The fermentation is carried out at pH 6.8 and at a temperature between 25.degree. C. and 35.degree. C., and the production with respect to a carbon source is then achieved in 50% and 70% yields. In aspects of economic consideration, however, the cost of carbon substrate such as carbohydrate is relatively high, and the development of a new fermentation system which can use other cheap carbon sources has been required.